The present disclosure relates generally to medical devices and, more particularly, to airway devices, such as tracheal tubes.
This section is intended to introduce the reader to aspects of the art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the course of treating a patient, a tube or other medical device may be used to control the flow of air, food, fluids, or other substances into the patient. For example, tracheal tubes may be used to control the flow of air or other gases through a patient's trachea and into the lungs, for example during patient ventilation. Such tracheal tubes may include endotracheal (ET) tubes, tracheotomy tubes, or transtracheal tubes. In many instances, it is desirable to provide a seal between the outside of the tube or device and the interior of the passage in which the tube or device is inserted. In this way, substances can only flow through the passage via the tube or other medical device, allowing a medical practitioner to maintain control over the type and amount of substances flowing into and out of the patient.
To seal these types of tracheal tubes, an inflatable cuff may be associated with the tubes. When inflated, the cuff generally expands into the surrounding trachea to seal the tracheal passage around the tube to facilitate the controlled delivery of gases via a medical device (e.g., through the tube). For intubated patients, the flow rate and volume of gas transferred into the lungs, which may vary according to the condition of each patient, may be controlled by the settings of a ventilator. One factor that is used to determine the ventilator settings may be an airway pressure measurement, which is typically obtaining by measuring the pressure along the breathing circuit (e.g., medical tubing connecting the tracheal tube to the ventilator) at a point outside the patient. Airway pressure measured in the breathing circuit at a point outside the patient may be a useful surrogate for the pressure in the lungs, which may in turn be used for calculating a number of ventilator settings, for example settings involving pressure limits.
However, in circumstances where the internal diameter of the tracheal tube is diminished, for example through the buildup of mucosal secretions that may partially block the airflow passage of the tracheal tube, the lung pressure may be lower than the airway pressure measurement taken outside the patient. Accordingly, an airway pressure measurement may not always serve as a reliable substitute for lung pressure measurements.